1. Field of the Invention
The present invention relates to a relay method, a relay apparatus, and a computer product for relaying a communication between a client and a server.
2. Description of the Related Art
Conventionally, in a system in which a server provides service to a client via a network, in addition to a main server that provides the service, a standby server that operates as an alternative machine of the main server when a fault occurs in the main server, and a relay apparatus that relays a communication between the server and the client are provided for a purpose of improving reliability of the system.
When a fault occurs in the main server, the relay apparatus performs a fault recovery processing. In the fault recovery processing, the relay apparatus switches a working server from the main server to the standby server, thereby continuing provision of the service in the system (for example, see Japanese Patent Application Laid-Open No. 2003-256297).
However, the relay apparatus relays a communication between the client and the server in an application layer. Therefore, at the time of switching the working server to the standby server, a determination on whether connection in the application layer can be maintained depends on an application. Consequently, a general fault recovery independent from the application cannot be performed.
Therefore, in a conventional relay apparatus, an independent fault recovery processing performed by the relay apparatus is required to be developed for each application. Since the relay between the client and the server is carried out in the application layer, a load of relay processing is large compared to when the relay is carried out in a transmission control protocol (TCP) layer.